diff --git a/doc/fern.txt b/doc/fern.txt
index 9beb3392..7069b091 100644
--- a/doc/fern.txt
+++ b/doc/fern.txt
@@ -24,6 +24,7 @@ MAPPING					|fern-mapping|
   FILE					|fern-mapping-file|
   DICT					|fern-mapping-dict|
 GLOSSARY				|fern-glossary|
+DEVELOPMENT				|fern-development|
 CHANGELOG				|fern-changelog|
 
 
@@ -961,6 +962,12 @@ GLOSSARY						*fern-glossary*
 			window.
 
 
+=============================================================================
+DEVELOPMENT						*fern-development*
+
+There is |fern-develop.txt| as an API documentation for fern plugin developer.
+
+
 =============================================================================
 CHANGELOG						*fern-changelog*